android MVP 設計模式

 MVP 全稱：Model-View-Presenter。主要邏輯如下：

 MVP 全稱：Model-View-Presenter。主要邏輯如下：

1. View。也就是Android中的Activity。同時需要創建一個View的抽象接口View interface。需要View實現的接口，View通過View interface與Presenter進行交互，降低耦合。

2. Model。用來操做實際數據（譬如數據存儲等）。有時也需要創建一個Model的抽象接口Model interface用來降低耦合。

3. Presenter。作為View與Model交互的中間紐帶，處理與用戶交互的負責邏輯。  

   優點如下：(1)降低耦合度

     (2)模塊職責劃分明顯

     (3)利于測試驅動開發

     (4)代碼復用

     (5)隱藏數據

     (6)代碼靈活性
缺點：  需要增加很多類。
  
  但是相比優點而言，缺點可以忽略。


 具體的demo代碼如下：


MainActivity:

public class MainActivity extends Activity implements IUserView,

OnClickListener {

private TextView showView;

private EditText username_et;

private EditText password_et;

private Button login_btn;

private Button getuserinfo_btn;

private Presenter pre;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

bindView();

setListener();

}

private void setListener() {

login_btn.setOnClickListener(this);

getuserinfo_btn.setOnClickListener(this);

}

private void bindView() {

showView = (TextView) this.findViewById(id.showView);

username_et = (EditText) this.findViewById(id.username_et);

password_et = (EditText) this.findViewById(id.password_et);

login_btn = (Button) this.findViewById(id.login_btn);

getuserinfo_btn = (Button) this.findViewById(id.getuserinfo_btn);

pre = new Presenter(this);

}

@Override

public void setUser(UserInfo info) {

showView.setText("用戶名為:" + info.getUsername() + ",密碼為:"

+ info.getPassword());

}

@Override

public UserInfo getUser() {

UserInfo info = new UserInfo();

String password = password_et.getText().toString().trim();

String username = username_et.getText().toString().trim();

if (TextUtils.isEmpty(username)) {

toast("用戶名不能為空");

return null;

}

if (TextUtils.isEmpty(password)) {

toast("密碼不能為空");

return null;

}

info.setPassword(password);

info.setUsername(username);

return info;

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.login_btn:

pre.saveInfo(getUser());

break;

case id.getuserinfo_btn:

pre.getUserInfo(); 

break;

default:

break;

}

}

private void toast(String msg) {

Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();

}

}

實體bean：

創建UserInfo 實體類

public class UserInfo {

private String username;

private String password;

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

@Override

public String toString() {

// TODO Auto-generated method stub

return username + ":" + password;

}

}

Model 抽象層

public interface UserModel {

public UserInfo getUserInfo();

public void setUserInfo(UserInfo info);

}

 

Model具體實現層：

public class UserModelImp implements UserModel {

UserInfo info = new UserInfo();

@Override

public UserInfo getUserInfo() {

return info;

}

@Override

public void setUserInfo(UserInfo info) {

this.info = info;

}

}

 

數據交互實現層：

public class Presenter {

private UserModel userModel;

private IUserView IuserView;

public Presenter(IUserView userView) {

this.IuserView = userView;

userModel = new UserModelImp();

}

public void saveInfo(UserInfo info) {

userModel.setUserInfo(info);

}

public void getUserInfo() {

IuserView.setUser(userModel.getUserInfo());

}

}

 View數據抽象層：

public interface IUserView {

public void setUser(UserInfo info);

public UserInfo getUser();

}